NAME
dacs_mailbox_test
- Test if a mailbox access will succeed.
SYNOPSIS
DACS_ERR_T dacs_mailbox_test ( DACS_TEST_MAILBOX_T rw_flag, de_id_t de, dacs_process_id_t pid, int32_t *mbox_status)
| Call parameters |
|
| rw_flag |
Flag to indicate which mailbox to test:- DACS_TEST_MAILBOX_READ: test the read mailbox to see if a call
to dacs_mailbox_read() will block, or
- DACS_TEST_MAILBOX_WRITE: test the write mailbox to see if a call
to dacs_mailbox_write() will block.
|
| de |
The DE owning the mailbox to test. |
| pid |
The process owning the mailbox to test |
| Return parameter |
|
| *mbox_status |
A pointer to the location where the mailbox status is
returned. The contents are:- set to zero if the mailbox will block, or
- set to non-zero if the mailbox will not block.
|
DESCRIPTION
The dacs_mailbox_test service
allows the programmer to test if the mailbox will block before calling dacs_mailbox_read() or dacs_mailbox_write().
RETURN VALUE
The
dacs_mailbox_test service
returns an error indicator defined as:
- DACS_SUCCESS: normal return.
- DACS_ERR_INVALID_ADDR: the pointer is invalid.
- DACS_ERR_INVALID_ATTR: the flag or enumerated constant
is invalid.
- DACS_ERR_INVALID_DE: the specified DE is either invalid
or not reserved.
- DACS_ERR_INVALID_PID: the specified PID does not refer
to an active process.
- DACS_ERR_INVALID_TARGET: this operation is not allowed
for the target process.